2009 Wilson IB Bio

There are two reasons why a structure might be shaped similarly in two different objects.  One is that the structure is analogous, meaning that it performs the same function.  The wings of a dragonfly and of a bird are analogous, and, in fact, are also analogous to the wings of a 747.  In order to fly an object needs to generate lift.  This is easily done (in various ways) by having large flat surfaces project out from both sides of the object.  Therefore flying things have such structures.

But knowing the function of a structure doesn’t necessarily tell us all we want to know about why the structure exists.  Part of why a wing exists is to perform a certain function, but part of it lies in the construction of the wing.  Perhaps this question is better worded as HOW the wing came to be rather than WHY it came to be.  The picture below shows the basic structure of the limbs of several vertebrates.  Notice that all the limbs, whether wings, legs, arms, or flippers are built upon the same basic structure.

ALL vertebrate limbs are put together this way, regardless of their use.  Clearly there is no analogous similarity between a bat’s wing and a horse’s leg, and the extreme difference in uses of the two makes the underlying similarity seem unusual.  These types of similarity are called homologous and are very interesting indeed.  

Biologists generally find depictions of angels absurdly funny because they have two sets of forelimbs.  Bird wings are homologous to human arms, not completely different structures.  Angels would necessarily have two tibia, two radii, two ulnae, and more than five sets of digits if they really looked like that, not to mention all the attachment bones that would have to be duplicated in the torso, like shoulder blades and collar bones.  Then there would have to be two sets of muscles, a huge sternum and keel, …  Even wimpy angels would be barrel-chested individuals indeed!  Pegasus, the flying horse of Greek myth, represents the same basic misunderstanding of anatomy.

http://itc.gsw.edu/faculty/bcarter/histgeol/paleo2/homol1.htm

From the past three days the biology and physic class took a trip to Watson Homestead. We were all divided up into seven groups and were told to do a lab that dealt with a stream and a pond. Some groups walked over to the stream as well as others driving to the pond collecting data based on their question. Afterwards we all reported back to the recreation center to discuss out collection of data with our group members. Most groups found bugs and examined them under a microscope. The biology students were told to find three organisms that were alike, and bring them back to school so they could be frozen. When we got back to school we had to dissect one organism and put it into an incubator. As for the for the other two, they were kept in alcohol and placed in the freezer.

http://www.youtube.com/watch?v=oE7sGyCBWr8&feature=fvhl

Stratafied sampling- takes into account different areas within the main habitat.

Random sampling- takes a broad view of a fairly uniform enviroment.

Chi-Squared test is used to see if two varaiables are associated or independent. They are generally used in data that has frequencies that have 5 or more repeating and done at random sampling. To do chi squared test you need a contingency table that shows the two way tables.

Equation -

                   answer squared=sum  (observed-expected)squared/expected

The equation and an example of a contingency table can be found at http://math.hws.edu/javamath/ryan/ChiSquare.html which isa pretty helpful website

The Cell Cycle is the division of cells in four main stages. The first stage is the  M phase, second is the G1 phase, third is the S phase and fourth is the G2 phase.

M phase- consists of Mitosis and Cytokinesis and it is the division of the mother cell into 2 daughter cells.

G1 phase- The interphase which is the phase in which the cell grows.

S phase- Where DNA replication and synthesis occure.

G2 phase- Where the cell is rapidly growing

Today we looked at graphs of biological science and we learned about osmosis and cell tissue. One graph was about the stages, and about protein difusion in membranes.

there are different types of species for clovers such as 

Trifolium pratense

L. the red clover and 

Trifolium repens

L. the white clover